- GLSLTest_ES3.MaxVaryingWithFeedbackAndGLline failed before because
  gl_Position takes up one slot from max varyings on Metal back-end.
  FIXED

- Previously, copyImage() between mips of the same texture would fail.
  Due to the read RenderTargetMtl is released before the copy happens.
  FIXED

- GL_DEPTH_COMPONENT24 texture data upload didn't work due to the source
  32 bit depth data wasn't handled properly.  FIXED

- D24S8 format will be disabled on AMD for now, it will be converted to
  D32S8 instead.

Bug: angleproject:2634
Bug: angleproject:5235
Bug: angleproject:5242
Change-Id: Ie7082f0545c0885ce5ec72df8a7ec4ee5d5de4b1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2494525
Commit-Queue: Le Hoang Quyen <le.hoang.q@gmail.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>